"You see, Watson," he explained in the early hours of the morning
as we sat over a glass of whisky and soda in Baker Street, "it
was perfectly obvious from the first that the only possible
object of this rather fantastic business of the advertisement of
the League, and the copying of the Encyclopaedia, must be to get
this not over-bright pawnbroker out of the way for a number of
hours every day. It was a curious way of managing it, but,
really, it would be difficult to suggest a better. The method was
no doubt suggested to Clay's ingenious mind by the color of his
accomplice's hair. The 4 pounds a week was a lure which must draw
him, and what was it to them, who were playing for thousands?
They put in the advertisement, one rogue has the temporary
office, the other rogue incites the man to apply for it. and
together they manage to secure his absence every morning in the
week. From the time that I heard of the assistant having come for
half wages, it was obvious to me that he had some strong motive
for securing the situation."

"But how could you guess what the motive was?"

"Had there been women in the house, I should have suspected a
mere vulgar intrigue. That, however, was out of the question. The
man's business was a small one, and there was nothing in his
house which could account for such elaborate preparations, and
such an expenditure as they were at. It must, then, be something
out of the house. What could it be? I thought of the assistant's
fondness for photography, and his trick of vanishing into the
cellar. The cellar! There was the end of this tangled clew. Then
I made inquiries as to this mysterious assistant and found that I
had to deal with one of the coolest and most daring criminals in
London. He was doing something in the cellar--something which
took many hours a day for months on end. What could it be, once
more? I could think of nothing save that he was running a tunnel
to some other building.

"So far I had got when we went to visit the scene of action. I
surprised you by beating upon the pavement with my stick. I was
ascertaining whether the cellar stretched out in front or behind.
It was not in front. Then I rang the bell, and, as I hoped, the
assistant answered it. We have had some skirmishes, but we had
never set eyes upon each other before. I hardly looked at his
face. His knees were what I wished to see. You must yourself have
remarked how worn, wrinkled, and stained they were. They spoke of
those hours of burrowing. The only remaining point was what they
were burrowing for. I walked round the corner, saw the City and
Suburban Bank abutted on our friend's premises, and felt that I
had solved my problem. When you drove home after the concert I
called upon Scotland Yard and upon the chairman of the bank
directors, with the result that you have seen."

"And how could you tell that they would make their attempt
to-night?" I asked.

"Well, when they closed their League offices that was a sign that
they cared no longer about Mr. Jabez Wilson's presence--in other
words, that they had completed their tunnel. But it was essential
that they should use it soon, as it might be discovered, or the
bullion might be removed. Saturday would suit them better than
any other day, as it would give them two days for their escape.
For all these reasons I expected them to come to-night."

"You reasoned it out beautifully," I exclaimed in unfeigned
admiration "It is so long a chain, and yet every link rings
true."

"It saved me from ennui," he answered, yawning. "Alas! I already
feel it closing in upon me. My life is spent in one long effort
to escape from the commonplaces of existence. These little
problems help me to do so."

"And you are a benefactor of the race," said I.

He shrugged his shoulders. "Well, perhaps, after all, it is of
some little use," he remarked. " 'L'homme c'est rien--l'oeuvre
c'est tout,' as Gustave Flaubert wrote to George Sand."